Studies will be conducted to determine the relationship of acetycholine levels to known different levels of inhibition of cholinesterase at selected stages of intoxication. Mice and insects will be treated in vivo with selected compounds which are known to result in widely different levels of inhibition of cholinesterase at each of several stages of intoxication. Acetylcholine levels in insects intoxicated with selected organochlorines will be examined also. Techniques of TLC and pyrolysis-GLC will be utilized. The effects of intoxication of mice and insects with the above selected compounds on production, release and inactivation of catechol amines will be examined by histofluoromicroscopic, radioisotopic, radioautographic and GLC techniques.